I'm considering doing rack deads for back strength and mass.
I know very well what a stiff-legged deadlift is; I know what a sumo deadlift is; and I know what a regular deadlift is. I have at one time or another used a variation of all of the above.
My question is, how is a rack deadlift performed and how is it different from the above mentioned? Also what are the benefits of doing these as opposed to regular deads?